1. Field of the Invention
The present invention refers to a quick-recharging energy feeding system for means of transport, in particular of the collective type, with electric traction.
2. Description of Prior Art
As known, the type of motor traction currently known and used more or less experimentally depends on chemical sources or vectors, which bring about strong penalties in terms of efficiency. All other arrangements, such as for example hydrogen, cannot claim use efficiencies exceeding 7% of the originally invested energy. Moreover, currently, in the scientific world, intense discussions are held about the limit represented by batteries, in particular as regards the weight to be transported. The enormous improvement of performances of batteries of accumulators disclose the possibility of approaching the order of magnitude of autonomies obtained with liquid fuels. Currently, the most promising accumulators use lithium polymers, but their use on portable telephones and computer has already demonstrated their foreseeable extraction limits. Moreover, the life cycle of these accumulators is also a problem: in fact, following a small number of recharge cycles, they drastically reduce their performance, imposing a replacement of the whole battery pack, that in case of the electric traction, is composed of a few quintals of costly manufactured products both for producing them and for disposing or recycling them.
In such context, the term “feeding” defines a partial recharge of the batteries that are a piece of equipment of an autonomous electric means of locomotion. The term is used to point out the recharge operation that it is possible to perform, using currently available technologies, when the locomotion means stops in suitably equipped areas (for example, the terminus of urban and extra-urban bus lines). Current arrangements suffer the intrinsic impossibility of traditional accumulators to accept high recharging currents and the need of reducing to a minimum the vehicle stop times, de facto compelling to perform only partial battery recharges. The state of the art of the feeding technology, adopted by some urban transport companies on lines served by minibuses (12 places, 10.5 tons), has as characteristic an extension of the daily autonomy of electric vehicles, which anyway require a slow recharge during the night before being able to restart the service.
The technology to transfer very high electric powers on vehicles is anyway already known with pantograph of railway locomotives. The chance of exploiting not very short stops of the electric vehicle (on the order of 10 minutes) is also known, to perform a partial recharge of the accumulators in order to increase their daily autonomy.
Currently, the state of the art of conductive or inductive feeding techniques does not allow, with the same vehicle sizes, to extend the autonomy of electric vehicles to the kilometers traveled provided by operating plans of endothermic vehicles used for collective transport. Moreover, the need of having at least 10 minutes available every hour to perform a partial recharge of the accumulators, does not allow extending the advantages of the electric traction outside the strictly urban context.
The art further proposed a simpler system for implementing the braking regeneration on vehicles operated by an endothermic motor as disclosed in European Patent Application n. 6018745.7, filed on Jul. 9, 2006 by the same Applicant. In particular, the described system is substantially a smart battery that uses super-capacitors coupled with a power electronics that complement the electrochemical vehicle battery. This coupling allows high energy savings, modulating the effects depending on accelerations.
Currently, culture and art, but above all investments related to infrastructures dedicated to transports on tires, are such as to be able to support the chance of demanding to the infrastructures themselves, and therefore the territory, some of the needs of the vehicle, from autonomy to actual traction members.